Lacking in IMDb credits as she may be, "Les Misérables" star Samantha Barks is no newcomer to performing: Before being chosen to belt out the part of Eponine in Oscar-winning director Tom Hooper's adaptation of the musical, Barks played Eponine in the West End stage production of the show, as well as the 25th anniversary cast.

A professional performer since the age of 3, Barks is experienced well beyond her 22 years, and now has bragging rights for a lifetime. She worked alongside big names such as Hugh Jackman and Helena Bonham Carter on the movie, and recently spent an evening jumping on a couch and singing with Amanda Seyfried. Barks sat down with NextMovie in New York City ahead of "Les Misérables"' Christmas Day release and dished on karaoke, being a lifelong theater geek and how often she goes out partying.

What was your favorite part of working on "Les Misérables"?

For me, the highlight was getting to be around such an incredible cast and director. Being in the hands of Tom Hooper, who I consider one of the most intelligent people I've had the pleasure of meeting, let alone working with. Seeing how he works, his eye for detail, his dedication to the novel and this live vocal, was so exciting. And seeing somebody like Hugh Jackman, his incredible state of calm. He's the most calm person. Then when somebody yells action, he just kicks into his role. He's an incredibly inspiring person to watch.

That was me, Annie [Hathaway] and Amanda [Seyfried]. We went and sang karaoke in New York all through the night. I sang Elvis. Annie sang "Don't Rain On My Parade" and it was amazing. Amanda kind of did some interesting '90s rap. It was very well-varied night. We had so much fun with it, we all ended the night jumping around on the couch singing "Girls Just Wanna Have Fun." It was pretty epic. A very epic "Les Mis" karaoke night.

So do you do a lot of karaoke? What are your favorite songs to sing?

I get nervous singing karaoke, actually. Yeah, it's weird. But I love singing "Black Velvet," I love singing some Johnny Cash, which is interesting because it's in a guy's key, I love singing Elvis Presley. I just sing the songs that people don't expect you to sing, because I just love having fun at karaoke and I'm always a bit nervous to sing something serious. I love to sing random stuff. That's exciting for me.

You said that you learned a lot from your fellow cast members. Anyone in particular?

I think I learned a lot from Eddie [Redmayne], getting to work so up close and personal with him. The way he works with the camera, when you watch his performance back, everything he does is so smart. He's a really smart actor. He does so much research and seeing how deep he went into finding out about his character, how much work he did, and he's such an intelligent actor. That really shows through, all the work he did and all the details he put into this role. And I love him.

I've read the book twice now and I've listened to it countless times. I've performed it eight times a week for about a year. My math is bad, but that's a lot of shows. It feels wonderful, it feels so exciting to go see it and get lost in that "Les Mis" world. There's something about "Les Mis" that just moves me, and so I love going to watch anytime I can catch it. I'm a "Les Mis" geek.

Is it your favorite musical?

It depends on what mood I'm in. "Les Mis" is one of the classics that I loved growing up, that was one of the ones that made me want to sing. There's other musicals like "Wicked," that was the turning point that made me want to do it as a career, because it had this amazing contemporary sound to it. I started to get into musical theater because I did have a contemporary sound and the musicals were starting to merge that. The great thing about "Les Mis" is that Eponine as a character doesn't necessarily have to have a legitimately classical sound. I found that after singing the role of Eponine and getting it in the West End, I feel so thrilled to be able to play it.

How does your performance change between playing Eponine on stage in front of a live audience and playing her on film?

When you're on stage you have to project your voice to 2,000 seats, to reach very far away. You have to fill the room. You also have to project your emotions, so that everyone can kind of read what you're trying to say, your character. On screen, it's so much more intimate. All the little flickers of your eye, all the details that you're trying to add, can be read. So it means you can be more intimate, but you also have to be a lot more detailed. For us, we were looking at a lot more detail into the characters.

There were also some details in the storyline changed: In the musical, Cosette gives Eponine the letter to give to Marius, which she does, making her slightly more appealing. In the novel, she's got a slightly more twisted morality, she comes from a darker place. And so in the film she steals the letter that's meant for Marius and doesn't give it to him, meaning he goes to war, so it kind of has a knock-on effect and gives you more of an insight into the kind of mind that she has. It's not a straightforward, "I love him, so I'll do that for him," although in the end she does do a good deed: she gives him the letter. It has kind of a redeeming quality. She's kind of redeemed by her love for him.

Is there one medium that's easier for you, between stage and screen?

No, because neither are easy, because they both have their challenges, but they're different challenges. So on stage, you know, doing eight shows a week for a year, you are kind of dedicating your life to being in great vocal shape, so that's not going out partying your nights away — some people do, some people can get away with it, but I try and reign that aspect in — you hold back on your alcohol, you drink a lot of water, you steam, you drink lemon and honey, you have to look after yourself. It's like being an athlete, but on a different scale.

The thing is with [film], it's a shorter amount of time, but it's a more intense amount of time, doing a film. So you have to be vocally prepared to perform at 5 a.m. That's very different.

A lot of people will never make it to a theater to see "Les Mis" live. What's it like knowing that for a ton of people, you are the only face they'll see when they think of Eponine?

Pressure. Pressure! It's iconic! It's an iconic role that I always loved, being a kid, and to be able to be a part of this character feels like a huge honor for me. I think this is great, because it's giving people a chance to come and access theater. When I was growing up, I grew up on a small island called the Isle of Man, north of England. I didn't have the opportunity to come see West End shows. For me, if I was younger, being able to watch a combination of cinema and live theater like this, I would have loved it. It feels like something to be a part of which is making theater more accessible.

Everyone involved in the movie is very excited about the live singing on set, but are there any other movie musicals that you like?

There's so many. I think "Les Mis" specifically works being done live, but no other musical has done this yet, in this capacity. But I love "Chicago," because "Chicago" is something different. it still works being done pre-recorded, but that doesn't affect anything because it's being taken out of real life and put into a theatrical sense. That's the way that story's designed, and I love that story. I mean, Catherine Zeta Jones in that role in "Chicago" is just utterly the most incredible thing ever. She's amazing. I think other musicals absolutely have worked, but this one really just worked being done live.

What did you do with your first Hollywood paycheck?

I'm really boring. You know what, I'm not flashy with my cash. I'm always eager to invest and kind of be smart with my money, which is the most boring answer, but it's something I've grown up kind of feeling was so important, owning property and trying to invest for tomorrow, is kind of my motto with things. It's boring, but that's what I do. I've looked after my money. As I started working around my third birthday, my first check went straight to the bank.

Whose career would you like to emulate?

Catherine Zeta Jones, actually, she's an inspiration to me. She's got an incredible way of using screen and theater, and has an incredibly balanced, varied career but also just phenomenal. I just love her. She's very beautiful.